JPH11102854A - Wafer cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer-cleaning device wherein even cleaning solution of low volatilization can be dried effectively in a short time. SOLUTION: Supply amount for each of NMP(N-methyl pyrolidone) stored in a tank 10 and IPA(isopropyl alcohol) stored in a tank 20 is adjusted by liquid mass flow controllers 15, 25, and they are fed to a binary nozzle 40. In the binary nozzle 40, two kinds of cleaning solutions NMP, IPA are mixed according to each supply amount, and the mixed cleaning solution is discharged from a nozzle tip part 45 to a circumferential edge part of a wafer W whereto polyimide is attached. Since IPA is soluble in NMP as well as as has high volatilization, NMP wherefrom polyimde is removed in a circumferential edge part of the wafer W can be evaporated and dried effectively in a short time, along with IPA.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate cleaning apparatus for cleaning a peripheral portion of a thin plate-like substrate (hereinafter simply referred to as "substrate") such as a semiconductor substrate or a liquid crystal glass substrate having a film formed on a main surface. .

[0002]

2. Description of the Related Art Generally, the above-mentioned substrate is sequentially subjected to various processes such as a resist coating process, an exposure process, a developing process, and a heating process and a cooling process associated therewith, so that a desired substrate process is performed. ing. Then, the substrate to be processed is circulated and transported by the substrate transport robot in accordance with a predetermined processing procedure between the processing units performing the above-described processing.

Meanwhile, among various processes for a substrate, there is a process using a chemical solution. For example, a resist solution is used in the resist coating process, and a developing solution is used in the developing process. In addition, polyimide or SOG (Sp
In some cases, a treatment for applying a chemical such as in-on-glass is performed.

When a chemical solution adheres to the transfer arm of the substrate transfer robot when transferring the substrate on which the chemical treatment has been performed, when the transfer arm holds a new substrate, the chemical solution is transferred to clean the substrate. Contamination may occur. In particular, polyimide among the chemicals is applied to protect the main surface of the substrate, but is known to have high adhesiveness, and may adhere to a new substrate when attached to the transfer arm. If the transfer arm sticks the substrate, it is not preferable because excessive stress is applied to the substrate when the substrate is transferred.

Therefore, a dedicated nozzle (hereinafter referred to as an EBR (Edge-Bead-Remote), which discharges a cleaning liquid to the peripheral portion of a substrate coated with polyimide to remove the polyimide in the portion.
ver) nozzle). Since the peripheral portion of the substrate is not used as an element such as a semiconductor and need not be protected, there is no problem even if polyimide is removed. Further, since the transfer arm of the substrate transfer robot holds the end of the substrate, removing the polyimide on the peripheral portion of the substrate eliminates the possibility that the polyimide will adhere to the transfer arm.

[0006]

By the way, conventionally, EBR has been used to remove the polyimide at the peripheral portion of the substrate.
The cleaning liquid discharged from the nozzle includes N-methylpyrrolidone (hereinafter, “NMP”) having high solubility in polyimide.
) Is used. NMP has a feature that it has high solubility in polyimide but low volatility. This causes the following problem.

FIG. 3 is a diagram for explaining a conventional substrate peripheral edge cleaning process. The polyimide P in the peripheral portion WE of the substrate W has been removed by the NMP discharge from the EBR nozzle. Since NMP used for removing the polyimide P has low volatility, it is dried by so-called spin drying. That is, the NMP remaining on the substrate W is dried by rotating the substrate holding member 90 and the substrate W sucked and held by the substrate holding member 90 by a motor (not shown).

However, it is necessary to rotate the substrate W for a long time and at a high speed in order to dry the NMP. Then, as shown in the figure, when the drying process is performed for a long time at a rotation speed at which the NMP can be dried, the polyimide P gradually seeps out from the center of rotation due to the centrifugal force due to the rotation, and eventually the EBR nozzle. The polyimide P adheres again to the peripheral portion WE of the washed substrate W, which may cause the above-mentioned transport failure.

The present invention has been made in view of the above problems, and has as its object to provide a substrate cleaning apparatus capable of efficiently drying even a cleaning liquid having low volatility.

[0010]

According to a first aspect of the present invention, there is provided a substrate cleaning apparatus for cleaning a peripheral portion of a substrate having a film formed on a main surface thereof. A first cleaning liquid supply means for supplying a first cleaning liquid capable of dissolving the above components, and (b) a second cleaning liquid for dissolving the first cleaning liquid and supplying a second cleaning liquid having a higher volatility than the first cleaning liquid. 2 cleaning liquid supply means, (c) first cleaning liquid supply amount adjusting means for adjusting the supply amount of the first cleaning liquid, and (d) second cleaning liquid supply amount adjusting means for adjusting the supply amount of the second cleaning liquid. And (e)
A mixing unit configured to mix the first cleaning liquid and the second cleaning liquid to generate a mixed cleaning liquid; and (f) a discharge unit configured to discharge the mixed cleaning liquid to a peripheral portion of the substrate.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a substrate cleaning apparatus according to the present invention. This apparatus is an apparatus that discharges a cleaning liquid to a peripheral portion of a substrate W coated with polyimide to remove the polyimide in the portion.

In order to remove the polyimide, it is necessary to use NMP (first cleaning liquid) that can dissolve the polyimide. However, since NMP has low volatility and may cause the above-described problems, the substrate cleaning apparatus according to the present invention dissolves NMP and has high volatility in isopropyl alcohol (hereinafter referred to as “IPA”). Is mixed with NMP so as to be able to discharge. The substrate processing apparatus according to the present invention is configured so that the mixing ratio between NMP and IPA (second cleaning liquid) can be accurately and stably controlled. Hereinafter, the configuration will be described in order.

NMP and IPA are stored in tank 1
0 and stored in the tank 20 as a liquid. NMP and IPA are pressurized by gas from pressurized gas supply means 30 connected to tanks 10 and 20 (in this embodiment, the pressure of nitrogen gas or helium gas is applied).
The liquid mass flow controller (LMFC) 1
5 and 25 respectively.

The liquid mass flow controllers 15, 25 are
It has a function of controlling the supply amounts of NMP and IPA to flow rates specified in advance. That is, through the liquid mass flow controllers 15 and 25, NMP and IPA are stably supplied at a predetermined supply amount.

The NMP and the IPA whose supply amounts are adjusted by the liquid mass flow controllers 15 and 25 are sent to the two-fluid nozzle 40, respectively. The two-fluid nozzle 40 is
It has a function of mixing two types of cleaning liquids NMP and IPA in accordance with the respective supply amounts, and supplying the mixed cleaning liquid to the nozzle tip (discharge means) 45.

The nozzle tip 45 discharges the mixed cleaning liquid to the periphery of the substrate W coated with polyimide. The substrate W is configured to rotate during and after the discharge of the mixed cleaning liquid from the nozzle tip 45 for a predetermined time. That is, the substrate W is held in a horizontal posture by the turntable 50, and a rotary shaft 11 of a motor (not shown) is vertically provided at the center of the lower surface of the turntable 50. Then, the rotation of the motor is performed by the rotation of the substrate W
Will be rotated.

According to the above-described structure, IPA that is dissolved in NMP and has higher volatility than NMP is mixed with NMP and discharged to the peripheral portion of the substrate W. Quickly evaporates with IPA
Dried. That is, since NMP is also efficiently dried by IPA, it is not necessary to rotate the NMP for a long time and at a high speed as when only NMP is dried. Therefore, the polyimide does not ooze out and adhere to the peripheral portion of the substrate W, and there is no fear that a conveyance failure occurs.

Further, since NMP and IPA can be supplied from one system of nozzles, it is possible to dispose the nozzle tip 45 in a smaller space than when discharging each from a plurality of separate nozzles. is there.

Next, an example of a substrate peripheral portion cleaning process in the substrate cleaning apparatus will be described. In the substrate cleaning apparatus according to the present invention, the supply amounts of NMP and IPA are stably adjusted by the liquid mass flow controllers 15 and 25, and are mixed by the two-fluid nozzle 40 according to the supply amounts. Therefore, it is possible to stably adjust the mixing ratio of NMP and IPA in the mixed cleaning liquid discharged to the peripheral portion of the substrate W to an arbitrary ratio.

FIG. 2 is a diagram showing an example of the transition of the mixing ratio of NMP during the cleaning process of the peripheral portion of the substrate. In the figure,
The vertical axis indicates the mixing ratio of NMP in the mixed cleaning solution, and the horizontal axis indicates the time after the start of the substrate peripheral edge cleaning process.

As shown in the figure, from the start of the cleaning process to the time t ₁ , the NMP mixture ratio is 1.0, that is, the cleaning process is performed only with NMP. During this period, the main purpose is to dissolve the polyimide, and the higher the concentration of NMP, the more efficiently the purpose can be achieved.

Next, from time t ₁ to time t ₂ , the supply amount of NMP is gradually decreased and the supply amount of IPA is gradually increased, so that the mixing ratio of NMP in the mixed cleaning liquid is gradually reduced. During this period, the NMP is replaced with IPA while dissolving the polyimide with NMP, and the NMP adhering to the substrate W is gradually replaced with IPA over time. At time t ₂ , the NM in the mixed cleaning solution is
The mixing ratio of P becomes 0 (the mixed cleaning liquid becomes only IPA), and at the same time, the discharge of the mixed cleaning liquid from the nozzle tip 45 is stopped.

Finally, during a period from time t ₂ to time t ₃ , a so-called spin dry process is performed in which the discharge of the mixed cleaning liquid is stopped and drying is performed while rotating the substrate W. At the time of time t _2, the cleaning liquid adhering to the substrate W is generally replaced by IPA, the drying process can be performed in a short time.

As described above, a series of substrate peripheral edge cleaning processes are performed. This makes it possible to efficiently remove the polyimide at the peripheral portion of the substrate W and to dry the mixed cleaning solution in which the polyimide is dissolved in a short time. Therefore, the polyimide does not ooze out due to the rotation of the substrate W and does not adhere again to the peripheral portion of the substrate W.

Further, NMP and IP in the mixed cleaning solution
Since the mixing ratio with A is stably adjusted, the reproducibility of the processing result and the processing time of the substrate peripheral edge cleaning processing is good. The substrate peripheral edge cleaning process is also one step in circulating the substrate according to a predetermined processing procedure, and the reproducibility of the processing result and the processing time is an important factor in the process.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above example. For example, in the above embodiment, NMP and IPA are mixed. However, the present invention is not limited to this, and any form may be used as long as the processing liquid is dissolved in a certain cleaning liquid and has a higher volatility than the cleaning liquid. .

Further, the cleaning process of the peripheral portion of the substrate is not limited to the example shown in FIG. 2. For example, IPA may be mixed to some extent immediately after the start of the cleaning process.
NMP may be contained in the mixed cleaning solution at the time point _{2 at} a predetermined mixing ratio.

[0029]

As described above, according to the present invention,
First cleaning liquid supply means for supplying a first cleaning liquid capable of dissolving components of a film formed on the main surface of the substrate; and a second cleaning liquid dissolved in the first cleaning liquid and having a higher volatility than the first cleaning liquid. A first cleaning liquid supply amount adjusting means for adjusting the supply amount of the first cleaning liquid, a second cleaning liquid supply amount adjusting means for adjusting the supply amount of the second cleaning liquid,
A mixing means for mixing the cleaning liquid and the second cleaning liquid to generate a mixed cleaning liquid, and a discharge means for discharging the mixed cleaning liquid to the peripheral portion of the substrate. Even if the cleaning liquid is a low-volatile cleaning liquid, the cleaning liquid is efficiently evaporated and dried together with the second cleaning liquid in a short time. Also,
Since the mixing ratio between the first cleaning liquid and the second cleaning liquid is stably adjusted, the reproducibility of the processing result and the processing time of the cleaning processing is good.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a substrate cleaning apparatus according to the present invention.

FIG. 2 is a diagram illustrating an example of a transition of a mixing ratio of NMP during a substrate peripheral edge cleaning process of the substrate cleaning apparatus of FIG. 1;

FIG. 3 is a view for explaining a conventional substrate peripheral edge cleaning process.

[Explanation of symbols]

 10, 20 tank 15, 25 liquid mass flow controller 40 two-fluid nozzle 45 nozzle tip W substrate

Claims (1)

[Claims] 1. A substrate cleaning apparatus for cleaning a peripheral portion of a substrate having a film formed on a main surface thereof, comprising: (a) a first cleaning liquid supply means for supplying a first cleaning liquid capable of dissolving components of the film; (B) second cleaning liquid supply means for dissolving the first cleaning liquid and supplying a second cleaning liquid having a higher volatility than the first cleaning liquid; and (c) controlling the supply amount of the first cleaning liquid. First cleaning liquid supply amount adjusting means for adjusting; (d) second cleaning liquid supply amount adjusting means for adjusting the supply amount of the second cleaning liquid; and (e) the first cleaning liquid and the second cleaning liquid. A substrate cleaning apparatus, comprising: mixing means for mixing to generate a mixed cleaning liquid; and (f) discharging means for discharging the mixed cleaning liquid to a peripheral portion of the substrate.